Intel® PXA255 Processor Developer’s Manual 4-3

System Integration Unit
For more information on alternate functions, refer to the Source Uni t column in Table 4- 1 for the appropriate section of this document.Table 4-1. GPIO Alternate Functions (Sheet 1 of 4)
Pin Alternate
Function Name Alternate Function
Assignment AF{n}
encoding Source Unit Signal Description and comments
GP1 GP_RST ALT_FN_1_IN 01 Cl ocks & Power
Manager Unit Active low GP_reset
GP6 MMCCLK ALT_FN_1_OUT 01 Multimedia Card
(MMC) Controller MMC Clock
GP7 48MHz clockALT_FN_1_OUT 01 Clocks & Power
Manager Unit 48 MHz clock output
GP8 MMCCS0 ALT_FN_1_OUT 01 Multimedia Card
(MMC) Controller
MMC Chip Select 0
GP9 MMCCS1 ALT_FN_1_OUT 01 MMC Chip Select 1
GP10 RTCCLK ALT_FN_1_OUT 01 System Integation
Unit real time clock (1Hz)
GP11 3.6MHz ALT_FN_1_OUT 01 Clocks & Power
Manager Unit
3.6MHz oscillator out
GP12 32kHz ALT_FN_1_OUT 01 32kHz out
GP13 MBGNT ALT_FN_2_OUT 10
Memory Controller
memory controller grant
GP14 MBREQ ALT_FN_1_IN 01 memory controller alternate bus
master request
GP15 nCS_1 ALT_FN_2_OUT 10 Active low chip select 1
GP16 PWM0 ALT_FN_2_OUT 10 PWM0 output
GP17 PWM1 ALT_FN_2_OUT 10 PWM1 output
GP18 RDY ALT_FN_1_IN 01 Ext. Bus Ready
GP19 DREQ[1] ALT_FN_1_IN 01 External DMA Request
GP20 DREQ[0] ALT_FN_1_IN 01 External DMA Request
GP23 SCLK ALT_FN_2_OUT 10
SSP Serial Port
SSP clock
GP24 SFRM ALT_FN_2_OUT 10 SSP Frame
GP25 TXD ALT_FN_2_OUT 10 SSP transmit
GP26 RXD ALT_FN_1_IN 01 SSP receive
GP27 EXTCLK ALT_FN_1_IN 01 SSP ext_clk
GP28
BITCLK ALT_FN_1_IN 01 AC97 Controller Unit AC97 bit_clk
BITCLK ALT_FN_2_IN 10 I2S Controller I2S bit_clk
BITCLK ALT_FN_1_OUT 01 I2S bit_clk
GP29 SDATA_IN0 ALT_FN_1_IN 01 AC97 Controller Unit AC97 Sdata_in0
SDATA_IN ALT_FN_2_IN 10 I2S Controller I2S Sdata_in
GP30 SDATA_OUT ALT_FN_1_OUT 01 I2S Controller I2S Sdata_out
SDATA_OUT ALT_FN_2_OUT 10 AC97 Controller Unit AC97 Sdata_out
GP31 SYNC ALT_FN_1_OUT 01 I2S Controller I2S sync
SYNC ALT_FN_2_OUT 10 AC97 Controller Unit AC97 sync
GP32 SDATA_IN1 ALT_FN_1_IN 01 AC97 Controller Unit AC97 Sdata_in1
SYSCLK ALT_FN_1_OUT 01 I2S Controller I2S S ystem Clock